The invention relates in general to apparatus for killing weeds and thinning crops, and in particular to apparatus for facilitating selective application of an electrical current to individual plants to be killed. Some prior art proposals have suggested the selective application of electricity to plants to be killed by utilizing a hand-held device, however for various reasons such proposals have not been commercially successfull. U.S. Pat. No. 1,661,030 for example suggests the use of a conductive knife blade on an elongated pole, attached to an AC electrical source with grounding poles, for facilitating plant destruction by cutting and supplying a current thereto. Such a device is impractical to operate and unsafe, however, since it does not allow an operator complete freedom of movement and requires an operator to handle a member that is continuously charged, and requires the operator to perform a cutting motion.
According to the present invention, apparatus is provided for allowing selective destruction of plants without the safety hazards present in prior art devices, and with complete freedom of movement. A source of high-voltage, high-amperage electrical current (AC or DC) is mounted on a vehicle adapted to traverse a field where weeds are to be killed and/or crops to be thinned. Electrically connected with the current source are one or more members adapted to be held by an operator and for selectively applying current from said source to a plant to be destroyed. The member includes a "stick" portion of non-conductive material, and a tip portion of conductive material. An operator controlled switch is mounted on the stick portion for selectively making and breaking the electrical path between the current source and the conductive tip portion. The switch is in a low-voltage secondary control circuit for controlling the high-voltage circuit. Ground contact for the vehicle on which the current source is mounted is provided by a sharpened wheel or chain or the like which provides ground contact as the vehicle is moving and does not require the operator to remove and reinsert grounding poles from and into the ground when it is necessary to change the range of the device. Plant destruction is effected by merely bringing the conductive tip portion into contact with a plant. Safety interlock means for the electrical equipment may also be provided.